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1.
Leila Ghorbani Dr. Pooran Golkar Dr. Reza Jafari Dr. Mohsen Ahmadi Dr. Alireza Allafchian 《化学与生物多样性》2023,20(9):e202300811
This study evaluated several secondary metabolites, essential oils (EOs) compositions, and antioxidant activity in four medicinal plants that originated in Isfahan rangelands. The species were Astragalus verus, Astragalus adscendens, Daphne mucronata, and Phlomis olivieri. Thirty-two genotypes of these species were evaluated for different biochemical traits. Based on the evaluation of EOs compounds, GC/MS analysis revealed the total number of identified compounds. These compounds were 25, 22, 12, and 22 for A. adscendens, A. verus, D. mucronata, and P. olivieri, respectively. The dominant compounds were phthalate (59.88 %) in A. adscendens, phytol (38.02 %) in A. verus, hexanoic acid (32.05 %) in D. mucronata and β-cubebene (30.94 %) in P. olivieri. Phytochemical analysis showed that D. mucronata, A. adscendens, and P. olivieri had the highest total phenolics content (TPC) (18.24 mg gallic acid equivalent/g dry weight), total flavonoids content (5.57 mg QE/g DW), and total anthocyanins content (0.23 mg/g DW), respectively. The highest total chlorophyll (0.27 mg/g DW), total carotenoids (0.03 mg/g DW), and antioxidant activity (71.36 %) were observed in A. adscendens, A. adscendens and A. verus, respectively. Among all genotypes, the highest TPC (20.1 mg GAE/g DW) was observed in genotype 5 of D. mucronata. This study provided new information on the chemical compounds within the distribution range of these ecologically dominant rangeland species in Isfahan province, Iran. The data revealed that superior genotypes from these species are rich in natural antioxidants and bioactive compounds. Thus, they can be used in ethno pharmacological fields, food, and industrial applications. 相似文献
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Hideaki Yamada Miyako Osakai Yoshikazu Izumi 《Bioscience, biotechnology, and biochemistry》2013,77(8):2039-2045
Various bacteria which can grow on biotin as a sole carbon source were isolated from soil samples. These bacteria were classified into three groups according to the biotin-degrading pattern. Cell-free extracts from all these bacteria grown on biotin possessed high biotinyl-CoA synthetase activities. Cultural conditions for strain No. 166, the highest biotinyl-CoA synthetase producer, were examined. Biotinyl-CoA synthetase was induced in the presence of biotin, but not in the presence of any other carboxylic acids or biotin intermediates. The addition of lactose and yeast extract to the medium enhanced both the growth and the enzyme activity. The enzyme reaction for biotinyl-CoA synthesis required ATP, CoA and Mg2+ as well as biotin. From taxonomical studies, bacterium No. 166 was identified as a strain of Mycoplana. 相似文献
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In our study, Central and Eastern European bee pollens of different botanical origins were compared, based on their antioxidant and color properties. Total phenolic content (TPC), total flavonoid content (TFC), and in vitro antioxidant capacity (by FRAP, CUPRAC, ABTS⋅+ and DPPH⋅ assays) were determined spectrophotometrically. Besides, Relative Antioxidant Capacity Indexes (RACI) were calculated. CIELAB color parameters (L*, a*, b*, chroma) were determined by using a tristimulus-based instrument. Potential correlations between the investigated parameters were also identified. Based on the results of the preliminary study, ethanol:distilled water (60 : 40) was chosen as an extraction solvent. The total phenolic content of our samples ranged between 9.41 and 27.49 mg GAE/g dw. Pollens showed TFC:TPC ratios between 9 and 44 %. RACI values indicate that rapeseed (Brassica napus), traveller's joy (Clematis vitalba) and phacelia (Phacelia tanacetifolia) pollens have relatively high, while pollens of certain plants of the Asteraceae family possess low antioxidant potential. Antioxidant properties correlated significantly in most cases. RACI values showed strong positive correlation with each of the other antioxidant capacity parameters, suggesting that this approach is well applicable for comparing the antioxidant potential of bee pollens. No clear correlation was found between the antioxidant and color parameters. 相似文献
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Koichi Ogata Yoshikazu Izumi Yoshiki Tani 《Bioscience, biotechnology, and biochemistry》2013,77(5):1079-1085
By the addition of actithiazic acid, or acidomycin (ACM), to culture media, the accumulation of desthiobiotin by various microorganisms was enhanced from two-fold to about seventyfold, while that of biotin was markedly reduced. Especially, Bacillus sphaericus accumulated 350 μg per ml of biotin-vitamers assayed with Saccharomyces cerevisiae. ACM was not incorporated into the desthiobiotin molecule by resting cells of B. sphaericus. The amount of biotin-vitamers assayed with S. cerevisiae which was synthesized from pimelic acid by the resting cells grown with ACM was twice as great as that synthesized by the cells grown without ACM. From these results, the mechanism of the controlling action of ACM on biotin biosynthesis was discussed. 相似文献
5.
Multiple New Genes That Determine Activity for the First Step of Leucine Biosynthesis in Saccharomyces Cerevisiae 总被引:4,自引:0,他引:4
The first step in the biosynthesis of leucine is catalyzed by α-isopropylmalate (α-IPM) synthase. In the yeast Saccharomyces cerevisiae, LEU4 encodes the isozyme responsible for the majority of α-IPM synthase activity. Yeast strains that bear disruption alleles of LEU4, however, are Leu(+) and exhibit a level of synthase activity that is 20% of the wild type. To identify the gene or genes that encode this remaining activity, a leu4 disruption strain was mutagenized. The mutations identified define three new complementation groups, designated leu6, leu7 and leu8. Each of these new mutations effect leucine auxotrophy only if a leu4 mutation is present and each results in loss of α-IPM synthase activity. Further analysis suggests that LEU7 and LEU8 are candidates for the gene or genes that encode an α-IPM synthase activity. The results demonstrate that multiple components determine the residual α-IPM synthase activity in leu4 gene disruption strains of S. cerevisiae. 相似文献
6.
Casagrande R Georgetti SR Verri WA Jabor JR Santos AC Fonseca MJ 《AAPS PharmSciTech》2006,7(1):E64-E71
The present study evaluates the antioxidant activity of the flavonol quercetin, and its functional stability as a raw material
and when added in formulations. The iron-chelating activity was determined using the bathophenanthroline assay, and the functional
stability was evaluated with the antilipoperoxidative assay. Raw material presented concentration-dependent antilipoperoxidative
and iron-chelating activities. The initial antilipoperoxidative activity of the raw material, cream and gel-cream were 63%,
78%, and 69%, respectively. There was no detectable loss of activity during 182 days (6 months) of storage at all tested temperatures
(4°C, room temperature [RT], 37°C, and 45°C) for the raw material. Considering the method variability of 10%, activity loss
greater than 10% for nonionic cream was detected after 126 days at 4°C (20.1%), decreasing thereafter to 22.2% after 182 days.
At 45°C, the loss of activity started after 182 days (13.2%). For the anionic gel-cream, activity loss started after 84 days
(28.4%, 45°C), decreasing after 182 days to 40.3% at 45°C. At 37°C, activity loss was detected after 182 days (12%). In conclusion,
the results suggest that the activity of quercetin depends on iron chelation, and its posible usefulness as a topical antioxidant
to prevent oxidative stress-induced skin damage depends on maintaining its antilipoperoxidative activity stored at RT, which
avoids special storage conditions.
Published: February 3, 2006 相似文献
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Ammar Saleem Cory S. Harris Muhammad Asim Alain Cuerrier Louis Martineau Pierre S. Haddad John T. Arnason 《Phytochemical analysis : PCA》2010,21(4):328-339
Introduction – Ericaceae medicinal plants are traditionally used by the Eeyou Istchee Cree and other northern peoples of North America to treat type 2 diabetic symptoms. Because of the importance of phenolics as potential cures for degenerative diseases including type 2 diabetes, an analytical method was developed to detect them in the leaf extracts of 14 Ericaceae plants. Objective – To develop an optimised method which is applicable to a relatively large number of Ericaceae plants using their leaf extracts. For this purpose phenolics with a wide range of polarity, including a glucosylated benzoquinone, two phenolic acids, three flavanols, a flavanone, a flavone and five flavonols, were included in this study. Methodology – Characterisation of phytochemicals in extracts was undertaken by automated matching to the UV spectra to those of an in house library of plant secondary metabolites and the authentication of their identity was achieved by reversed phase‐high‐performance chromatography–diode array detection–atmospheric pressure chemical ionisation/mass selective detection. Results – Twenty‐six phenolics were characterised within 26 min of chromatographic separation in 80% ethanol extracts of 14 Ericaceae plants. The calibration curves were linear within 0.5–880 µg/g dry mass of the plant with regression values better than 0.995. The limits of detection ranged from 0.3 for µg/mL for (+)‐catechin to 2.6 µg/mL for chlorogenic acid. This is a first study dealing with relatively large number of Ericaceae extracts and is applicable to other plants of same family. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Luis Toronjo-Urquiza Adelina E. Acosta-Martin David C. James Tibor Nagy Robert J. Falconer 《Biotechnology progress》2020,36(4):e2980
Catechin compounds have potential benefits for recombinant monoclonal antibody (Mab) production as chemical additives in cell culture media. In this study, four catechin compounds catechin (Cat), epicatechin (EC), gallocatechin-gallate (GCG), and epigallocatechin-gallate (EGCG) were added to cell culture media (at 50 μM) and their effects on the recombinant Chinese hamster ovary (CHO) cell culture, specific productivity, and Mab quality were assessed. The results indicate that the improvement of specific productivity was linked to cell growth inhibition. All catechins caused cell phase growth arrest by lowering the number of cells in the G1/G0 phase and increasing the cells in the S and G2/M phases. Late addition of the catechin resulted in a significantly higher final IgG concentration. Cat and EC caused an improvement in the final antibody titer of 1.5 ± 0.1 and 1.3 ± 0.1 fold, respectively. Catechins with a galloyl group (GCG and EGCG) arrested cell growth and reduced cell specific productivity at the concentrations tested. The Cat-treated IgG was found to have reduced acidic species with a corresponding increase in the main peak. 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(12):2144-2147
The sex pheromone of Bombyx mori, bombykol [(10E,12Z)-10,12-hexadecadien-1-ol], can be biosynthesized in four steps: construction of a hexadecanoic moiety from acetyl CoA, ?-11-desaturation, .?-10,12-desaturation, and reduction of the acyl group. This biosynthesis is regulated by a hormone named the pheromone biosynthesis activating neuropeptide (PBAN). To examine the steps that are accelerated by this neurohormone, pheromone glands excised from decapitated females were incubated in vitro with either 14C-Iabeled sodium acetate or one of three fatty acids [hexadecanoic acid, (Z)-11-hexadecenoic acid, or (10E,12Z)-10,12-hexadecadienoic acid]. After analyzing the radioactivity that was incorporated from each precursor into bombykol and the biosynthetic precursors, it was observed that the first three steps proceeded in glands both treated and untreated with synthetic PBAN of B. mori; however, the last step proceeded only in the treated glands. From this in vitro experiment, it can be concluded that the main regulatory role of PBAN is in the reduction of the acyl group in B. mori, as was shown by our previous in vivo experiment. 相似文献
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The hydrocortisone-mediated induction of glutamine synthetase (GS) in the neural retina of the chick embryo is a characteristic and unique feature of differentiation of this tissue. The induction involves genomic activity elicited by the inducer resulting in synthesis and accumulation of the enzyme. We describe correlations between the growth of embryonic retina tissue in vivo and in vitro and the development of its inducibility for GS, and demonstrate that this development proceeds through two phases: competence-acquisition phase (before the 7th day of development), and maturation phase. BrdU applied for 24 h to retinas of 5-day embryos irreversibly suppresses the development of induction-competence. However, BrdU does not affect the progressive maturation of inducibility when applied to retinas that already are fully induction-competent (8 days and older). The short treatment with BrdU of 5-day retinas also causes defective histogenesis resulting in drastic malformation of the tissue. The nature of the processes involved in competence-acquisition and in the maturation of inducibility for GS are examined. Possible mechanisms by which BrdU prevents the development of induction-competence for GS in the early embryonic retina and elicits defective histogenesis are discussed. 相似文献
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Simon Mole 《Biochemical Systematics and Ecology》1993,21(8):833-846
The systematic distribution of tannins in foliar tissues has not been comprehensively reviewed for the Angiosperms in over 20 years. Here their systematic distribution is assessed using data based on protein precipitation or chemically specific tests. Fewer families are characterized by the typical presence of tannins than has previously been reported, and a greater variation in the occurrence of tannins in species sampled from within single plant families has been detected. This study presents the proportion of tannin-containing species in angiosperm families arranged according to the system of Cronquist for the first time. The potential utility of these data in testing ecological ideas about the distribution of tannins, such as those based on plant habit or life-history, is discussed. 相似文献
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Historically, oak woodlands of northern California have been subject to intensive tree and brush removal efforts to improve land for livestock grazing. As a result of this tree removal, these watersheds are susceptible to soil erosion and stream degradation. Therefore, planting woody vegetation is often required to restore watershed function. Prior to such actions, a thorough understanding of natural vegetation regeneration patterns is essential. The physical and biological attributes of natural vegetation regeneration in a cleared watershed were characterized using remote sensing, a Geographic Information System, and field surveys. A 79‐ha watershed at the University of California's Hopland Research and Extension Center was examined because the clearing of vegetation was part of a well‐documented experiment in the early 1960s, providing essential baseline data. The results of this study reveal that significantly more oak regeneration, consisting mostly of evergreen oaks, occurred on moister and steeper northerly slopes. Deciduous oaks, located primarily on drier and less steep southerly slopes, have not regenerated. Hardwood regeneration was associated with Josephine, Los Gatos, and Maymen soils. The distribution of hardwood regeneration is clustered, suggesting that the presence of other trees may promote regeneration. These results also suggest that without active restoration efforts such as tree planting and seedling protection, southerly slopes will most likely remain barren and erosion will continue, while northerly slopes and riparian areas will recover under the current land management practices. Despite some woody plant regeneration, the once densely forested watershed is now predominantly grassland, emphasizing the need to minimize clearing of California oak woodlands. 相似文献
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《PloS one》2015,10(3)
The identification of nursery grounds and other essential fish habitats of exploited stocks is a key requirement for the development of spatial conservation planning aimed at reducing the adverse impact of fishing on the exploited populations and ecosystems. The reduction in juvenile mortality is particularly relevant in the Mediterranean and is considered as one of the main prerequisites for the future sustainability of trawl fisheries. The distribution of nursery areas of 11 important commercial species of demersal fish and shellfish was analysed in the European Union Mediterranean waters using time series of bottom trawl survey data with the aim of identifying the most persistent recruitment areas. A high interspecific spatial overlap between nursery areas was mainly found along the shelf break of many different sectors of the Northern Mediterranean indicating a high potential for the implementation of conservation measures. Overlap of the nursery grounds with existing spatial fisheries management measures and trawl fisheries restricted areas was also investigated. Spatial analyses revealed considerable variation depending on species and associated habitat/depth preferences with increased protection seen in coastal nurseries and minimal protection seen for deeper nurseries (e.g. Parapenaeus longirostris 6%). This is partly attributed to existing environmental policy instruments (e.g. Habitats Directive and Mediterranean Regulation EC 1967/2006) aiming at minimising impacts on coastal priority habitats such as seagrass, coralligenous and maerl beds. The new knowledge on the distribution and persistence of demersal nurseries provided in this study can support the application of spatial conservation measures, such as the designation of no-take Marine Protected Areas in EU Mediterranean waters and their inclusion in a conservation network. The establishment of no-take zones will be consistent with the objectives of the Common Fisheries Policy applying the ecosystem approach to fisheries management and with the requirements of the Marine Strategy Framework Directive to maintain or achieve seafloor integrity and good environmental status. 相似文献
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Phylogenetic analysis of the bacterial communities in Lake Baikal bottom sediments in the region of subsurface methane hydrate discharge has been carried out using data on 16S rRNA sequences. The composition of these microbial communities is shown to be different in different horizons. Methanotrophic bacteria are found in the surface layer (0–5 cm), and uncultured bacteria constitute a great portion of this population. In deeper sediment layers (92–96 cm), a change in the microbial community occurs; specifically, a decreased homology with the known sequences is observed. The new sequences form separate clusters on a phylogenetic tree, indicating the possibly endemic nature of the bacteria revealed. Organisms related to the genus Pseudomonas constitute the main portion of the population. An archaea-related sequence was found in a horizon containing gas hydrate crystals (100–128 cm). Uncultured bacteria remain predominant.__________Translated from Mikrobiologiya, Vol. 74, No. 3, 2005, pp. 370–377.Original Russian Text Copyright © 2005 by Shubenkova, Zemskaya, Chernitsyna, Khlystov, Triboi. 相似文献
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Mack Sobhany Yoshimitsu Kakuta Nobuo Sugiura Koji Kimata Masahiko Negishi 《The Journal of biological chemistry》2012,287(43):36022-36028
Bifunctional chondroitin synthase K4CP catalyzes glucuronic acid and N-acetylgalactosamine transfer activities and polymerizes a chondroitin chain. Here we have determined that an N-terminal region (residues 58–134) coordinates two transfer reactions and enables K4CP to catalyze polymerization. When residues 58–107 are deleted, K4CP loses polymerase activity while retaining both transfer activities. Peptide 113DWPSDL118 within this N-terminal region interacts with C-terminal peptide 677YTWEKI682. The deletion of either sequence abolishes glucuronic acid but not N-acetylgalactosamine transfer activity in K4CP. Both donor bindings and transfer activities are lost by mutating 677YTWEKI682 to 677DAWEDI682. On the other hand, acceptor substrates retain their binding to K4CP mutants. The characteristics of these K4CP mutants highlight different states of the enzyme reaction, providing an underlying structural basis for how these peptides play essential roles in coordinating the two glycosyltransferase activities for K4CP to elongate the chondroitin chain. 相似文献
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《Journal of molecular biology》2022,434(2):167410
DNA polymerases maintain genomic integrity by copying DNA with high fidelity, part of which relies on the polymerase fingers opening-closing transition, a series of conformational changes during the DNA synthesis reaction cycle. Fingers opening and closing has been challenging to study, mainly due to the need to synchronise molecular ensembles. We previously studied fingers opening-closing on single polymerase-DNA complexes using single-molecule FRET; however, our work was limited to pre-chemistry reaction steps. Here, we advance our analysis to extensible substrates, and observe DNA polymerase (Pol) conformational changes across the entire DNA polymerisation reaction in real-time, gaining direct access to an elusive post-chemistry step rate-limiting for DNA synthesis. Our results showed that Pol adopts the fingers-closed conformation during polymerisation, and that the post-chemistry rate-limiting step occurs in the fingers-closed conformation. We found that fingers-opening in the Pol-DNA binary complex in the absence of polymerisation is slow (~5.3 s?1), and comparable to the rate of fingers-opening after polymerisation (3.4 s?1); this indicates that the fingers-opening step itself could be largely responsible for the slow post-chemistry step, with the residual rate potentially accounted for by pyrophosphase release. We also observed that DNA chain-termination of the 3′ end of the primer increases substantially the rate of fingers-opening in the Pol-DNA binary complex (5.3 → 29 s?1), demonstrating that the 3′-OH residue is important for the kinetics of fingers conformational changes. Our observations offer mechanistic insight and tools to offer mechanistic insight for all nucleic acid polymerases. 相似文献